1. Field of the Invention
The present invention relates to a protection device for a storage unit (a refill unit) of ink cartridges utilized in an ink jet printer.
2. Description of the Related Art
An ink jet printer known in general has a housing in which a print head, one or more ink tanks (ink cartridges), and a carriage is installed. The print head includes a nozzle for discharging ink, and is arranged on the carriage. The carriage is able to move in the perpendicular direction with respect to a printing medium (a sheet of printing paper, for example); that is, the carriage is able to move in the main scanning direction. The print head is connected to the ink tank, and discharges the ink provided therefrom via the nozzle. The printing medium is conveyed through the housing of the ink jet printer, and the ink discharged from the nozzle is printed thereon.
The ink jet printers can be roughly categorized into two types: an on-carriage type, and an off-carriage type. Such categorization can be made based on the arrangement of the ink cartridge. The on-carriage type and the off-carriage type both include a storage unit, or a storage case for detachably storing the ink cartridge. The on-carriage type has the storage unit arranged on the movable carriage. With this type of carriage, the ink is provided directly from the storage unit to the print head. On the other hand, the off-carriage type has the storage unit arranged inside the housing, but not on the movable carriage. The ink cartridge stored in the storage unit is connected to the print head by a relaying member; for example, an ink tube. The ink is provided from the remote storage unit to the print head that is supported on the carriage via the ink tube.
With either of the types of ink jet printers as described above, the ink cartridge must be replaced with a new one, or be refilled, when the volume of remaining ink becomes insufficient.
With the typical types of ink jet printers as described above, the storage unit has an ink inducing member that provides ink to the print head. Correspondingly, the ink cartridge has a connecting portion, such as an ink providing valve. To provide the ink to the print head from the ink cartridge, the ink inducing member of the storage unit is connected to the connecting portion of the ink cartridge. In a case where the ink inducing member is in the shape of a narrow needle or tube, the ink inducing member is easily bent or broken in the course of installing and removing the ink cartridge to and from the storage unit. Thus, a guiding portion, for example, a plurality of guiding ribs or a guiding tube section are formed on the periphery of the ink inducing member, while an insert tube corresponding to the aforementioned guiding ribs or the guiding tube section is formed on the connecting portion of the ink cartridge, to insert therein.
Ink jet printers of both the on-carriage type and the off-carriage type undergo a print test before shipment. The print test is performed to confirm that the printing mechanism is functioning. In such a test, one or more ink cartridge is installed in the storage unit, and after the print test, the ink cartridge is removed from the storage unit before shipment. The ink inside the print head can be left or removed prior to shipment. In the case where the ink is removed from the print head, the print head is refilled with a preservative liquid which has the same characteristic as the ink without pigments or dyestuffs. Then, a protection device, such as a protection cap or a dummy cartridge (that is, a cartridge with no ink inside), is installed in the case to cover the ink inducing member. The protection device prevents the leakage of the ink or the preservative liquid (the term “liquid” will be used as the general term for both the ink and the preservative liquid in the description below). The surface of the print head on which the nozzle is arranged is also covered with a nozzle cap to prevent the leakage of the liquid, and for the protection of the nozzle. Such a technique is taught in the Japanese Patent Application Publications No. 2002-79690, No. 2004-230857, No. 2005-238857, No. 2003-54000, and No. 11-157094.
In the aforementioned techniques, a rubber cork or a rubber cap is arranged on the protection device. The ink inducing member and the rubber cork (see FIG. 3 of the Japanese Patent Application Publication No. 2002-79690) or a cap (see Japanese Patent Application Publication No. 2005-238857 and No. 2003-54000) of the protection device are connected and sealed so as to prevent the leakage therefrom.
Furthermore, in the aforementioned techniques, fastening members such as levers, hooks, or the like are utilized to fasten the installed protection device inside the storage unit. For example, in the technique taught in Japanese Patent Application Publication No. 2003-54000, a weight lever (that is, the fastening member) arranged on the storage unit fastens and holds the protection member pressed against the ink inducing member. Such configuration improves the sealing of the ink inducing member, and as the result, the leakage therefrom is prevented.
In the technique taught in Japanese Patent Application Publication No. 11-157094, the fastening member includes a handle rotatably connected to the storage unit in the vicinity of the opening of the storage unit by a shaft, a link plate whose end is connected to the handle and arranged along the bottom surface inside the storage unit, and a link lever connected to the opposite end of the link plate. In the teaching of the above-mentioned technique, the handle has two side plates and an attaching surface formed therebetween. In the course of inserting the protection device, it can be set on the link plate. By rotating the handle towards the protection device, the attaching surface makes contact with the rear side surface of the protection device, enabling it to push the protection device into the storage unit.
However, according to the above-mentioned teaching, a large number of components are required for constructing such configuration. Furthermore, with such configuration, when the ink cartridge is installed inside the storage unit, the fastening member is arranged below the bottom surface of the storage case. Hence, such space for the fastening member must be reserved, which causes the storage unit to occupy much more space.
Furthermore, in the teachings of the aforementioned techniques, the protection device is not guided in the course of inserting it into the storage unit. Though the position in a horizontal direction (the direction of insertion) to the ink inducing member can be maintained by the fastening members of the aforementioned techniques, the position of the protection member in the direction orthogonal to the direction of insertion (for example, the left and right direction, or the up and down direction with respect to the direction of the insertion) must be determined manually.
Hence, if the protection device is inserted into the storage unit in an inappropriate position or angle, the sealing of the ink inducing member becomes insufficient. As a result, liquid leakage and/or damages on the ink inducing member due to such inappropriate position may occur. For example, following impact from vibrations due to transportation, the seal between the protection device and ink inducing member may be loosened, resulting in ink leakage. Moreover, in such condition, the inappropriate position of the protection device may cause the ink inducing member to be bent or broken. A measure to prevent such undesirable conditions has been sought for.